Fluid-governed electric switch



Oct. 2, 1923. v 1,469,497

A. B. CONANT ET AL FLUID GOVERNED ELECTRIC SWITCH Filed Jan. 1921 2 Shaets-$heet 1 A. B. CONANT ET AL FLUID GOVERNED ELECTRIC SWITCH Filed Jan. 5. 1921 z'snbm-she t 2 Patented a. 2, 1923. f

UNITED STATES YJPALTENTX OFFICE.

' ALBERT B. 'commr, or NEWTON CENTER, AND nommb A. noosn, or BOSTON,

' MASSACHUSETTS.

FLUID-GOVERNED ELECTRIC SWITCH.

Application filed January 3, 1921. Serial No. 434,726.

T 0' all whom it may concern:

Be it known that we, ALBERT B. CONANT, a citizen of the United States, residing at Newton Center, in the county of Middlesex and State of Massachusetts, and LEONARD A. House, a citizen of the United States, residing at Boston, in the county of Suffolk and State of Massachusetts, have invented an Improvement in Fluid-Governed Electric phragm to operate, the switch member. The

range of movement of the diaphragm, usually a large disc, between the predetermined pres sure limits is relatively small and the speed of movement is practically imperceptible. Consequentlyl'quick-acting means have been employed intended rapidly to move the switch member between open and closed positions upon a predetermined'range of movementof the pressuregoverned piston. Such means has usually been a tensile spring'or equivalent connected between the 'movable switch member and a lever governed'by the piston arranged to be moved from one to the other side of the pivotal center of the movable switch member to move it between open and closed positions. Due to the extremely slow movement of the piston, as when pressure is being built up in a tank, the axis of the tensile spring may be positioned substantially in line with pivotal center of the switch member for a considerable period of time without being suificiently eccentric therewith.

to move the switch member to open position. lVith such a condition there is practically no, or at least insufficient, pressure between the stationary and movable switch members and arcing occurs; and the arcing may be accentuated because of the vibration of the switch and its support, and also because of the pulsation of the diaphragm piston at each stroke of the pump piston. -Very fre quently the stationary and movable switch members are weldedtogether so that the switch can not open, and if the automatic safety valve of the pump does not open, and it often. fails to open, either the motor burns out or the pressure tank bursts.

An object of this invention is to-provide a switch of the type above set forthwith means whereby it is constrained rapidly to move between open and closed poistions and will be strongly retained in closed positionaintil rapidly moved to open position; and, further, will not remain in a semi-open orfidead center position.

,A switch embodiying this object of the invention may inc ude a pivoted movable sw1tch-member, an operating lever, and a tensile spring connecting said lever and mm:- able switch member. Said lever may be arranged to be actuated by the pressure governed piston through a lost-motion connection and means may be provided by which said lever is moved rapidly from one side to the other of its pivot whereby rapidly to shift the tension of said spring from one to the other side of the pivot of the movable switch member thereby to cause it rapidly to move between open and closed positions.

Said means may, and preferably does, comprise the eccentric pivoting of said lever and movable switch member or it may com rise a second s ring connected with said ever and a fixed support arranged to be moved across the pivot of said lever subsequently to move the spring connected with the movable switch member across the switch member.

The pressure-governed means has usually comprised a fiat disc or diaphragm. In order to obtain a suflicient motion, the diaphragm is of considerable diameter and conpivot of :said

sequently the mechanism connected therewith is subjected to considerable pressure; and the mechanism must have relatively great strength and consequently be relative 1y massive.

A further object of the invention isfthe provision of a novel pressure-governed means or diaphragm adapted to have a rela tively great range of movement between-the predetermined pressure limits fora relative: 1y small total pressure to whichit issubjected, whereby the mechanismnassociated therewith may be of little mass and the actionthe more rapid. The small .total pressure. acts ing upon the components of the. dev1ce"results in greatly reduced friction and consequently the accuracy of the device is enhanced.

The pressure governed means or d1aphragm embodying my invention may comprise an elastic fluid-imperforate tube enclosed in a spring-coil casing adapted for fluid communication through its open end. An increase in fluid pressure will operate to expand the tube axially against the pressure of its spring casing, and the caslng will assist the tube to contract axially upon a reduction of internal fluid pressure. The spring casing will resist lateral expansion of the tube.

A further object is generally to mprove the construction and operation'of fluid-pressure and fluid-level governed electric switches.

Fig. 1 is a side elevation of a fluid pressure governed electric switch embodying our invention, the enclosing casing being broken away.

Fig. 2 is a rear elevation of Fig. 1.

Fig. 3 is a plan view of Fig. 1.

Fig. 1 is a front elevation of Fig. 1, illustrating more particularly the stationary and movable switch members.

Fig. 5 is a vertical section along line 6-6 of Fig. 3, illustrating the diaphragm tube in expanded and the switch in open position.

Fig. 6 is a detail in side elevation, of the mechanism on the point of moving the movable switch member into open position.

Fig. 7 is a side view of a modified form of the invention adapted for fluid-level, or float, control.

Fig. 8 is an enlarged detail of the movable switch member and illustrates more particularly the pivotal connection of the supporting bar for the bridging members with the frame of the movable switch member.

Ashere shown the fluid-pressure governed switch embodying the invention includes the base 10 adapted to be supported by the pipe 11, by which fluid connection is made with the pressure source as a tank or pump not shown. A standard or support ng-plate 12 extends above the base 10 and is adapted to support the switch members and the operating mechanism therefor. A casing 13 may enclose all mechanism and the side-walls thereof may be received in the groove 14 in the base 10. A U-shaped member 15 may be secured to the opposite ends of said plate 12 and extend upwardly thereabove in which the screw 16 carried by the casing 13 may be threaded, thereby to secure the casing in place.

The diaphragm embodying our invention comprises the fluid imperforate tube 17 formed of soft rubber or the like of relatively small internal diameter as contrasted with its length. The upper end of the tube is closed by the thickened and conically shaped upper end portion 18; and the lower end portion is formed with the outwardly extended flange 19 preferably somewhat thicker than the walls of the body of the tube. Preferably also, the lower portion of the tube adjacent the flange 19 is thickened internally for strength as indicated at 20. A spring-coil casing 21, the convolutions of which, in the contracted condition of the tube, preferably contact, encloses the tube and serves to support the tube against lateral deformation. The upper end of the casing is shaped to conform to the end of the tube and has the loop 22 by which to connect with the switch operating mechanism hereinafter to be described.

Said tube is vertically disposed on and has its flanged end received inand supported on the bottom wall 23 of an internally screw-threaded recess 24 in a boss 25 of the base 10 and said pipe 11 is adapted to be in fluid communication with said recess and the interior of said tube. The flange 19 of said tube is compressed against the bottom Wall 23 of said recess 24 by the collar 26 disposed over said tube and its spring-casing and threaded in said recess. Said collar is internally screw-threaded to receive the end-convolutions of said casing by which said casing and collar are fixed together. The tube 17 is thereby secured at its open end only and is free to expand along its length. In expanding, under pres- 7 sure, the convolutions of the casing will separate, as illustrated in Fig. 6 yet the extent of separation will be relatively small for the extreme axial expansion of the tube and the side walls of the tube will be amply supported by the convolutions of the springcoil against lateral deformation and possible rupture. The tube and its spring-casing are unsupported except at the lower end and consequently friction between it and other supporting members is absent so that the axial movement of the tube may be proportional to the pressure variation of the fluid within the tube. Due to the small cross-sectional area of the tube the total pressure on the closed end thereof is relatively small so that mechanism of small mass may be employed and but little friction will result at the pivotal connections between the components. The diaphragm and its casing are also free to bend laterally and expand or contract in any lateral displacement whereby extreme accuracy of alignment between it and the switch-operating mechanism is unnecessary.

The switch adapted to be operated by the tubular diaphragm above set forth is supported by and on the side of said supporting plate 12 opposite from said diaphragm. A double-pole switch is herein illustrated which includes the two sets or pairs of stationary switch-members or studs 28 and 29 carried b the insulating plate 30 secured to the side ace of said supporting plate 12. Said switch studs extend through apertures in and are insulated from said supporting plate 12 and are provided at the rear with the binding-means 31' for connection with circuit leads adapted to be passed through insulating bushings 32 in the base 10.

Said supporting-plate 12 is formed with the slot 33 therein adapted to permit movement of a tension spring hereinafter tobe described, and has two spaced arms or'ears 34 extended forwardly from the sides of said slot adapted to support the movable switch member and the switch operating mechanism.

The movable switch member includes the two spring bridging members 35 having the contact tips 35 thereon disposed in alignment with the stationary switch-members and secured by the screws 36 to the insulatingbar 37.

Said bar is carried by the depending frameincluding the two spaced arms 38 disposed between the ears 34 of the fixed support and pivoted on the pins 39 fixed in said ears;

and the intermediate connecting portion 40.

Said connecting portion 40 has the downwardly extended ear 42 on one side and the extension 43 on the other side of it; and said extension 43 has a portion 46 extended from it substantiall parallel with the connecting portion 40. The insulating bar 37 is received between said portions 40 and 46, and 42 and 43 and is spaced from said latter ortions 42 and 43 and is pivotally supporte on the rivet 41 which extends between and is fixed to saidportions 40 and 46. This arrangement facilitates. the engagement of the bridging members with the stationary switch members. Said ortions 42 and 43 prevent undue rocking oi the bar 37. Said portion 43 extends beyond the bar and has the slot 44- therein in which the body of a stop-screw 45 is received.' Said screw is removably secured in the supporting-plate 12 and its head 45 is adapted to engage said portion 43 whereby to limit the movement of the movable switch member. The switch-open position ofthe movable switch-member determines to some degree the low pressure at which the device will operate to close the motor circuit associated therewith; and the greater the distance of the movable switch member away from the stationary switch member, the lower will be the pressure at which the switch will be closed, and vice versa. For some purposes it may be desirable to arrange said screw 45 to be adjustable toward and away from said supporting plate 12 whereby to vary the switch closing pressure but, in many instances, this is not desirable and an unintelligent adjustment of said screw may destroy the quick acting properties of the switch. Said intermediate portion 40 is also formed with the upwardly extended ear 46 having the aperture 47 therein in which the lower end 48 of a ten-.

sile spring 49 is received by which the movable switch member is moved rapidly between open and closed positions.

Means are provided by which the other end of said spring is supported which ad mits of its being moved in both directions across the pivotal center of said movable switch member whereby to exert a spring pressure either to press the movable switch member forcibly against the stationary switch members or to pull the movable switch member into open position. Said supporting means comprises the vertically disposed or inverted U-shaped frame having the downwardly extended arms 50 pivotally supported on pins 51 carried by the ears 34 to the rear of the pins 39 and having the connecting portion 52 formed with the aper ture 53 therein in which the upper end of said spring 49 is connected.

In the more or less ordinary construction of fluid pressure governed switches, said arms 50 and arms 38 of the movable switchmember are concentrically pivoted with the result that when the ends of the spring and the pivot are in alignment there is practically no spring pressure on the movable switch member to maintain it in closed position; conse uently arcing occurs. It is an important 0 ject of thisinvention that said arms 50 and 38 be eccentrically pivoted, as shown, whereby the movable switch member can not be maintained in a dead-center position without positive tendency to move in either direction, as will hereinafter be ex-. plained.

The movements of said frame supporting the upper end of said spring 49 are controlled by a tripping frame having the horizontally and rearwardly extended arms 55 concentrically ivoted with said arms 50 on said ins 51. Said arms 55 are reflexed inward toward each other over and on opposite sldes of the loop-portion 22 of the spring-casing 21 of the tube diaphragm; and a pin 56 passed through said loop and apertures in said arms 55 serves to connect said arms to said dia hragm for movement. Said frame is formed also with the arms 57 which extend upwardlv beyond said arms 50 and have the oppositel disposed-inwardlydirected ears 58. SM ears are so spaced that the spring supporting frame is permitted a considerable amount of independent -movement, due to said spring 49, from one jected to but little pressure is as illustrated in Fig. 1; and the switch is closed and the pump may operate to increase the pressure in a storage tank.

As the fluid pressure increases the diaphragm expands axially and the convolutions of the spring-casing 21 separate as indicated in Fig. 6. The tripping frame is slowly rotated in a clockwise direction about its pivots 51 and moves the spring-supporting frame with it, thereby gradually moving tln ends of the spring into alignment with said pins 51. At some fluid pressure the spring-supporting frame will be moved to a position indicated in Fig. 6, wherein the ends of the spring and the pivot of said frame are substantially in alignment, and the frame is about to be pulled over by the action of the spring. In this condition, however, the spring is so eccentrically dis posed with relation to the pivot of the movable switch member that said switch member is positively held in closed position.

When the spring-supporting frame is moved slightly forward, the spring will be moved across the pivot of said frame and its ten sion will be exerted to move it rapidly to its extreme forward position against the forward stops 58 of said tripping frame. During its rapid forward movement, said frame will move its end of said spring rapidly across the pivot of the movable switch member and the tension of the spring will be rapidly shifted from a switch-closing tension to a switch-opening tension, and conse quently the movable switch member will be moved rapidly into open position. It will be noted that, with proper arrangement of the mechanism, there will be no point at which the movable switch member is held for an appreciable time without tendency either to move toward open or closed position.

In the modification illustrated in Fig. 7 the switch is arranged for operation by a float and for this purpose the tubular diaphragm is replaced by the lever 71 pivoted to the base 10 and arranged to be engaged by the stops 72 attached to the float cable 73. Said lever is connected through the link 74 with the switch mechanism; and the operation of the switch is the same as with the tubular diaphragm.

The operation of the device as the pressure is reduced and the diaphragm contracts axially. is essentially the same.

It is obvious that the invention may be embodied in other structures than those herein set forth.

lVe claim:

1. An electric switch having the combination of stationary and movable switch members, a fixed support having two spaced and extended arms, said movable switch member including two spaced and connected arms disposed between the arms of said fixed support, means pivotally connecting said arms, and switch operating mechanism including an operating frame having spaced and connected arms, means pivotally connecting the arms of said frame to the arms of said fixed support to the rear of the pivotal connection of the arms of said movable switchmember, a spring disposed between all of said arms and connected to said movable switch member and operating frame, and means to move said operating frame comprising a lever pivotally supported on the pivotal support for the operating frame having inturned ears between which an arm of said operating frame is loosely received.

2. An electric switch having the combination of stationary and movable switch members, a fixed support having two s need and extended arms, said movable switc h member including two spaced and connected arms, disposed between the arms of said fixed support, means pivotally connecting said arms, and switch operating mechanism including an operating frame having spaced and connected arms, means pivotally connecting the arms of said frame to the arms of said fixed support to the rear of the pivotal connection of the arms of said movable switchmember, a spring disposed between all of said arms and connected to said movable switch member and operating frame, and means to move said operating frame comprising a lever pivotally supported on the pivotal support for the operating frame having lost-motion connection therewith.

3. An electric switch having the combination of stationary and movable switch members, a fixed support having two spaced and extended arms, said movable switch member including two spaced and connected arms disposed between the arms of said fixed support, means pivotally connecting said arms, and switch operating mechanism including an operating frame having spaced and connecting arms, means pivotally connecting the arms of said frame to the arms of said fixed support to the rear of the pivotal connection of the arms of said movable switchmember, a spring disposed between all of said arms and connected to said movable switch member and operating frame, and means to move said operating frame comprising a lever pivotally supported on said fixed support having lost-motion connection with said operating frame.

4. An electric switch having the combination of stationary and movable switch members, a fixed support havin two s aced and extended arms, said movab e switc member including two spaced and connected arms disposed between the arms of said fixed support, means pivotally connecting said arms, and switch operatin mechanism including an operating frame aving spaced and conpivotally connected at theupper ends thereof to the arms of said fixed support, and

switch operating mechanism including a vertically disposed operating frame having spaced and connected depending arms, means pivotally connecting the arms of said frame to the arms of saidrfixed support to the rear of the ivotal connection of the arms of said movab e switch member, a spring disposed between all of said arms and connected to said depending movable switch-member and vertically disposed operating frame, and means to move said operating frame comprising a lever pivotally supported on the pivot of said operating frame and having lost-motion connection with said frame.

6. An electric switch having the combination of stationary and movable switch members, a fixed support having two spaced and extended arms, said movable switch member including two depending, spaced and connected arms disposed between and pivotally connected at the up er ends thereof to the arms of said fixed sup ort, and switch operating mechanism inc uding a vertically disposed operating frame having spaced and connected'depending arms pivoted to the arms of said fixed support to the rear of the ivotal connections of the arms of said movab e switch member, a spring disposed between all of said arms and connected to said movable switch member and operating frame, and means to move said operating frame having lost-motion connection therewith. i

7. An electric switch having the combina tion of stationary and movable switch members, said movable switch member including two spaced and connected arms, means pivotally supporting said arms at the ends thereof, and switch operating mechanism ineluding an operating frame having two spaced and connected arms, means pivotally supporting the arms'of said frame at the ,ends thereof and eccentrically with respect to the pivotal supports of the arms of the mdvable' switch members, a spring disposed.

between the arms of and connected to said movable switch member and operating frame, and means to 'move said operating frame to move said spring across the pivots of said operating frame whereby to, effect a continued movement of said frame under influen'ce of said spring alone.

8. An electric switch having the combination of a fixed support, stationary switchmembers carried thereby, a movable switchmember comprising a pivoted arm, and an insulated bridging member for the station? ary switch members carried by said arm, and operating means for said movable switch member comprising a pivoted operating arm,

a spring connecting said operating arm and.

the arm' of the movable switch member and movable across the pivotsof both of said arms, and means to move saidoperating arm to move said spring across the pivot of Said arm whereby to effect continued movement of said arm under influence of said spring alone.

9. An electric switch having the combination of a fixed support, two pairs of stationary switch-members carried thereby, a movable switch member comprising a pivoted arm, an insulating bar carried by and extended laterally on opposite sides of said arm, bridging members for each pair of stationaryswitch members carried by said insulating bar on opposite sides of said arm, and operating means for said movable switch member comprising a pivoted operating arm, a spring connecting said operating arm and the arm of the movable switch member and movable across the pivots of both of said arms, and means to move said operating arm to move said spring acrom the pivot of said arm whereby to effect continued movement of said arm under influence of said spring alone.

10. An electric switch having the combination of a fixed su port, two pairs of stationary switch-mem rs carried thereby, a movable switch-member comprising a pivoted arm, an insulating bar carried by and extended laterally on opposite sides of said arm, means pivotally connecting said bar with said pivoted arm for restricted angular movement transverse the vplane of said piyoted arm, bridging members for each pair of stationary switch members carried by said insulating bar on opposite sides of said arm,

and operating means for said movable switch member comprising a pivoted operat--' tinued movement of said arm under influence of said spring alone,

11. bination of a fixed support, two pairs of stationary switch-members carried thereby, a

movable switchmember comprisin a pivoted arm, an insulating bar carri by and An electric switch having the comextended laterally on opposite sides of said arm, means connecting said bar loosely with said pivoted arm arranged to permit it to move angularly with respect to said pivoted arm, bridging members. for each pair of stationary switch-members carried by said insulating bar on opposite sides of said arm, and operating means for said movable switch member comprising a pivoted operating arm, a spring connecting said operating arm and the arm of the movable switch member and movable across the pivots of both of said arms, and means to move said operating arm to move said spring across the pivot of said arm whereby to efiect continued movement of said arm under influence of said spring alone.

12. An electric switch having the combination of a fixed support, stationary switchmembers carried thereby, a movable switchmember comprising a pivoted arm, a bridging member for said stationary switch members, and means loosely connecting said bridging member with said arm, and operating means for said movable switch-member comprising a pivoted operating arm, a spring connecting said operating arm and the arm of the movable switch member and movable across the pivots of both of said arms, and means to move said operating arm to move said spring across the pivot of said arm whereby to effect continued movement of said arm under influence of said spring alone.

In testimony whereof, we have signed our names to this specification.

ALBERT B. CONANT.

LEONARD A. HOUSE. 

